[Mediawiki-l] emailconfirmed group won't display after upgrade

[HKairpost]

Hello,

On our setup only users with confirmed email can edit. We've just
upgraded from 1.12.1 to 1.15.1

From: Special:UserRights i see that no users are in the 'emailconfirmed'
group, even the ones that should have been put there (created before and
after upgrade).

Though everything works fine:
* New users that do not confirm their emails can't edit
* Once email confirm they can edit
* Old users with confirm email can edit

Should i do something about that? Or let as it is since it works as
expected?

Is it a known bug? I can provide more info if necessary.

Thanks
hka